A Comparative Analysis of Decommissioning Scenarios Based on Radiation Dose Modeling and Multi-criteria Decision Analysis for Oskarshamn Nuclear Reactor 3 : Lessons Learned from Operating Experience in the Reuse of Decommissioned Sites

Abstract: An increasing number of decommissioning activities are being undertaken worldwide at facilities where radioactive material has been produced, used, or managed, which will also be the case of the Oskarshamn nuclear reactor O3 in Sweden, the remaining operational unit at that power plant. Decommissioning, which seems to be the sign of ending, is, in fact, a future-oriented process that can prove successful the safe management of nuclear facilities throughout their entire lifetimes but especially after shutdown. In this context, this research aims to develop a comparative profile of decommissioning scenarios based on a radiation dose modeling approach using RESRAD-BUILD software. Conducting then a multi-criteria decision analysis (MCDA) of scenario comparison for the decommissioning of O3 is essential for updating on-going decommissioning projects, making strategic decisions for future ones, and bringing in sustainable site reuse options. The exposure-to-dose model will be used to evaluate and optimize safety parameters, site release levels particularly, related to personnel and the environment. Testing multiple sets of parameters in the decommissioning plan will be used to compare results and to assess the sensitivity of the strategy to variable inputs. This comparison with the MCDA Analytic Hierarchy Process model (AHP) results will allow the identification of the most optimal reuse scenario for Oskarshamn unit 3 after its useful life ends. Also, the lessons learned from operating experience in the reuse of decommissioned nuclear sites can be incorporated systematically into the eventual decommissioning of O3, and which, according to current planning will run until 2035 or 2045.